No xD Although Dieselpunk and Cyberpunk both are pessimistic, they use a different premise. In Dieselpunk the pessimism comes from the 2 World Wars and most of the war machinery was running on diesel. In Cyberpunk however, our world is highly developed and interconnected everywhere, through computers or nanotechnology inside of human bodies. Genetic engineering and enhancing the human body with machine parts (cyberware) to form cyborgs is a thing. In Dieselpunk there is no such combination of living things with machines.
Furthermore, the environment is depicted differently: Dieselpunk admires the mechanical parts of a machine (same like steampunk but without the optimism) but the emphasis lays on mechanical, so no electrical high-end stuff.
A Cyberpunk world often is flashy, with neonlights and advertisement panels everywhere and generally a lot of colorful light. There often are megacyties housing the enormous population of mankind on earth, which in turn are inspired by large cities like Tokio for example. I never have seen a grass plain in Cyberpunk, everywhere where there's not a skyscraper is a factory. Natural environment is completely missing. Cyberpunk kind of deals with the question "What happens with a highly technizized, but overpopulated world?" while Dieselpunk tries to depict the hard time after two World Wars with the style (in clothing, vehicles, architecture) of that time.